Ear infections in dogs

What is an ear infection?

The ear consists of three parts:

• Outer ear: auricle and external auditory canal
• Middle ear: eardrum, ossicles, and the so-called bulla
• Inner ear: the organ of balance and hearing

The medical term “otitis” refers to inflammation of part or all of the ear. In this article, we will focus on otitis externa, which is inflammation of the external ear canal. It is by far the most common type of ear infection in dogs.

‍

Causes and risk factors

An ear infection is usually caused by a combination of various factors.
Predisposing factors such as a narrow ear canal, floppy ears (for example, in Cocker Spaniels, Bassets, or Bloodhounds), dense hair in the ear canal (as seen in Poodles, Labradoodles, or Lagottos), or excessive earwax production (common in Cocker Spaniels, Labradors, and Springer Spaniels) significantly increase the risk of developing an ear infection.
Swimming and diving can also increase the risk, as moisture in the ear creates an ideal environment for bacteria. In addition, excessive cleaning of the ears or the use of cotton swabs can irritate the ear and thereby trigger or worsen an infection.

The primary factors that can trigger otitis are, above all, allergic skin conditions, which are by far the most common cause.
In young animals, parasites such as ear mites play an important role and can cause severe inflammation.
Obstructive conditions such as polyps, neoplasms, or foreign bodies can also cause otitis. Other primary causes include keratinization disorders and certain autoimmune diseases, which can also lead to inflammation of the ear canal.

Secondary factors, such as bacteria or Malassezia, are not the primary causes of otitis; rather, they take advantage of an already diseased or altered ear environment to multiply rapidly. This means that if the ear is already irritated or inflamed due to a primary cause—such as an allergy, parasites, a foreign object, or anatomical issues—the natural balance of microorganisms is disrupted. Bacteria or Malassezia, which can normally be found in small numbers in the ear, then multiply excessively and exacerbate the inflammation.

Recognizing the signs: these are the typical symptoms

When a dog has ear problems, it usually shows very clear signs of discomfort:

• shaking one's head
• Scratching one's ears
• Pain when touched
• Red, warm, or swollen ears
• Strong odor or discharge
• Head tilt (especially when the middle ear is affected)

diagnosis

A thorough examination is important to determine which pathogen is involved and how the inflammation developed. The veterinarian examines the ear canal, assessing redness, swelling, the nature of the discharge, and the condition of the eardrum. If there is a foreign object in the ear, it can often be detected during the otoscopy.
A cotton swab is also used to collect ear discharge, which is then examined under a microscope. This allows pathogens or cells to be identified:

• Bacteria (cocci or rods)
• Yeast fungi (Malassezia)
• parasites
• Inflammatory cells

A cytological examination is important for selecting the appropriate treatment.

It is not always possible to examine the ear immediately, as some dogs will not tolerate manipulation of the ear due to severe pain. In such cases, brief pre-treatment with anti-inflammatory medication is necessary so that the ear can be examined pain-free after a few days.
In severe cases or with otitis that does not heal, a bacteriological examination including an antibiogram is advisable to select the appropriate antibiotic therapy.
If a middle ear infection is suspected or a growth in the ear is suspected, further examinations such as video otoscopy or a CT scan are indicated.

therapy

Treatment depends on the pathogen, the severity of the condition, and the underlying cause.
Ear cleaning is a central component of treatment, as earwax and pus can significantly reduce the effectiveness of medications. Depending on the findings, ceruminolytic, aqueous, or mild cleansers are used. Cotton swabs should not be used for cleaning, as they can push the debris even deeper into the ear canal. After applying the cleaner, massage the outer ear canal for about 30 seconds—ideally, you should hear a splashing sound. Afterward, let the dog shake its head, and any excess fluid can be gently removed from the ear opening with a cotton ball. In this video, you’ll learn how to properly clean your dog’s ears.

In most cases, local treatment consists of ear drops that are administered at home. Depending on the diagnosis, they contain antibiotics, antifungal agents, and anti-inflammatory ingredients such as cortisone. For Malassezia infections or mixed infections, combination medications are often used, which are very effective.

Systemic treatment—for example, with tablets that act throughout the body—is necessary in certain situations, such as in cases of severe pain, significant swelling or narrowing of the ear canal, involvement of the middle ear, or when local treatment is not reliably possible. In such cases, glucocorticoids and/or systemic antibiotics—selected based on an antibiotic susceptibility test—are used.

Regular follow-up visits are essential to ensure that the inflammation has completely cleared up—because that’s the only way to prevent flare-ups.

Treating the underlying cause is particularly important, especially in cases of allergies, hormonal imbalances, or anatomical issues. Without addressing the underlying cause, relapses are common.

How can I prevent an ear infection?

Good prevention starts with teaching your dog early on to let you touch its ears without any fuss. This allows you to check its ears regularly and spot any changes quickly. Dogs with sensitive ears benefit from occasional cleaning with a mild ear cleaner suitable for dogs—but not too often, as excessive cleaning can actually promote inflammation. After bathing or swimming, the ears should be thoroughly dried to prevent moisture from accumulating in the ear canal.

Hair in the ear canal should generally not be plucked, as plucking can irritate the sensitive skin inside the ear and may even cause an infection. Only in rare cases—for example, if there is so much hair in the ear that topical medication cannot be applied—might it be appropriate to remove the hair. However, this should always be done only after consulting a veterinarian

What is the prognosis?

The prognosis depends heavily on whether the ear infection is a one-time occurrence or a chronic, recurring condition.
Sporadic acute otitis usually heals quickly with the right treatment—often within just a few days.
Chronic or recurrent cases are more difficult to treat. Allergies, anatomical peculiarities, or long-term inflammatory processes often play a role here. However, even persistent cases can be successfully treated with targeted diagnostics and a structured treatment plan.

If your dog suffers from allergies, a thorough allergy evaluation is especially important, as recurring ear infections are often linked to them. Regular veterinary checkups also help detect changes early on and prevent long-term problems.

‍

‍

‍

‍

‍